| This paper is mainly foused on a key project of Shanghai Constraction Group, which will be completed by the cooperation of Shanghai Tunnel Ltd and Tongji University.A new kind of shield------double partiality shield driven by hydraulic pressure jars(J-DPS) is introduced in this paper, which would fill up a blank of our state research. J-DPS has several advantages compared with traditional single axis shield. The latter has some disadvantages, such as big cutting power, tool wear asymmetry ,big- sized bearings and being unable to cut abnormity section. J-DPS can decrease manufacture cost, reduce construction expenses, save energy sources and bring us a lot of economic benefits.Because cutting wheel drive system and its structure are one of key techniques for the shield, so the author has done considerable study on drive system of J-DPS. The main contents of the research are as follows:1,Based on partiality whirling of J-DPS and principles of dynamics, the author established a math model of cutting wheel drive system. The moving rule for single hydraulic pressure jar is easily understood, accordingly moving rule for more jars is obtained, including the relations of tangential force,normal force,flux with defluxion angles. The result would provide theoretical analysis for cutting wheel structure design and cutter collocation.2,Cutting torque is accounted according to experience expressions. The author of this paper has designed and analyzed accesories of the cutting wheel, including the ralation between partial radius (r) and cutting wheel size; the number of axes and their supporing forms; structure of axes; dispose of axes; cutting wheel structure; cutter collocation and so on.3,Sheild structure is optimized accourding to genetic algorithm. The partiality radius,length and diameter of hydraulic pressure jars are all importent parameteres for shield structure. The author established Multi-objective and Multi-constraint genetic algorithm, coded with the real number. She also established Fitness Function, accounted with matlab genetic algorithm toolbox and gained optimized parameters.4,Hydraulic pressure jar directional inverting is cortrolled by a cam which is monitored by proximity switches. With hydraulic pressures jars, cutting wheels can have a smooth running. A hydraulic pressure system cortrolled by constant pump is designed and hydraulic pressure components are carefully slected. The author makes analysis for constant-power control of cutter of body system through constant power variable pumps. The costant power system can assure the steady rotate speed of cutter body system.5,The constant-flux systems and constant-power systems are analysed. The time domain models of constant-flux system and constant-power system are deduced . Systems are simulated through Simulink boxes of Matlab. The results indicate that the fluctuation of cutter body speed in constant-flux system is large while the fluctuation of cutter body speed in constant-power system is calm and stable.6,The double partiality shield withφ1.86m driven by hydraulic pressure jar has been designed and produced.7,A testing software is programmed. Relevant experiments have been done on analog shield platform. Dates are measured through press and speed sensors and graphs about rotate speed and press are drawn. The math model of cutting wheel is validated by experimental results. Theoretically, the experimental results have some errors. The possible reasons for the errors are discussed in details in this paper.
|
PDF Full Text Request